APA (7th ed.) Citation

Sacco, N., Vanzetti, B., Frankfurter, M. D., & Jackson, G. (1997). The letters of Sacco and Vanzetti. Penguin Books.

Chicago Style (17th ed.) Citation

Sacco, Nicola, Bartolomeo Vanzetti, Marion Denman Frankfurter, and Gardner Jackson. The Letters of Sacco and Vanzetti. New York: Penguin Books, 1997.

MLA (9th ed.) Citation

Sacco, Nicola, et al. The Letters of Sacco and Vanzetti. Penguin Books, 1997.